Colloids of polypyrrole nanotubes/nanorods: A promising conducting ink

Stable colloidal dispersions of polypyrrole (PPy) nanotubes/nanorods were obtained by the chemical polymerization of pyrrole in the presence of methyl orange and poly(N‐vinypyrrolidone). Due to extended morphology of colloidal particles, the films deposited from colloids with PPy nanotubes/nanorods had conductivity two orders of magnitudes higher than those from colloids of ordinary PPy nanoglobules. Dynamic light scattering measurement demonstrated that PPy nanotubes/nanorods have average particles sizes around 500 nm with a dispersity index around 0.3. The PPy colloids were stored over 3 months without visible agglomeration or precipitation. UV–vis spectra of PPy nanotubes/nanorods were recorded both in acidic or alkaline media. Raman spectra excited with 785 nm excitation laser confirmed the same mechanism of protonation of nanoglobular and nanotubular PPy. The colloid of PPy nanotubes/nanorods also exhibited good electrochemical redox activity, which makes them promising for the deposition of thin conducting layers used in sensors or energy-storage devices. The dispersions were used for the coating of films on poly(ethylene terephthalate) foils.